diff --git a/interfaces/cython/cantera/_cantera.pxd b/interfaces/cython/cantera/_cantera.pxd
index 97465d73b..955b9a29f 100644
--- a/interfaces/cython/cantera/_cantera.pxd
+++ b/interfaces/cython/cantera/_cantera.pxd
@@ -11,9 +11,14 @@ cdef extern from "cantera/base/xml.h" namespace "Cantera":
 cdef extern from "cantera/base/ctml.h" namespace "ctml":
     XML_Node getCtmlTree(string) except +
 
+cdef extern from "cantera/thermo/mix_defs.h":
+    cdef int thermo_type_surf "Cantera::cSurf"
+    cdef int thermo_type_edge "Cantera::cEdge"
+
 cdef extern from "cantera/thermo/ThermoPhase.h" namespace "Cantera":
     cdef cppclass CxxThermoPhase "Cantera::ThermoPhase":
         CxxThermoPhase()
+        int eosType()
         double pressure() except +
         double temperature() except +
         void setMoleFractions(double*) except +
@@ -21,6 +26,12 @@ cdef extern from "cantera/thermo/ThermoPhase.h" namespace "Cantera":
         int nSpecies()
         XML_Node& xml()
 
+cdef extern from "cantera/thermo/SurfPhase.h":
+    cdef cppclass CxxSurfPhase "Cantera::SurfPhase":
+        CxxSurfPhase()
+        double siteDensity()
+        void setSiteDensity(double)
+
 cdef extern from "cantera/kinetics/Kinetics.h" namespace "Cantera":
     cdef cppclass CxxKinetics "Cantera::Kinetics":
         CxxKinetics()
diff --git a/interfaces/cython/cantera/base.pyx b/interfaces/cython/cantera/base.pyx
index 395c9596a..a76c39af4 100644
--- a/interfaces/cython/cantera/base.pyx
+++ b/interfaces/cython/cantera/base.pyx
@@ -1,5 +1,5 @@
 cdef class _SolutionBase:
-    def __cinit__(self, infile, phaseid=''):
+    def __cinit__(self, infile, phaseid='', phases=()):
         rootNode = getCtmlTree(stringify(infile))
 
         # Get XML data
@@ -19,9 +19,13 @@ cdef class _SolutionBase:
 
         # Kinetics
         cdef vector[CxxThermoPhase*] v
+        cdef _SolutionBase phase
 
         if isinstance(self, Kinetics):
             v.push_back(self.thermo)
+            for phase in phases:
+                # adjacent bulk phases for a surface phase
+                v.push_back(phase.thermo)
             self.kinetics = newKineticsMgr(deref(phaseNode), v)
         else:
             self.kinetics = NULL
diff --git a/interfaces/cython/cantera/composite.pyx b/interfaces/cython/cantera/composite.pyx
index 3217c0728..e5d3a4e83 100644
--- a/interfaces/cython/cantera/composite.pyx
+++ b/interfaces/cython/cantera/composite.pyx
@@ -2,3 +2,5 @@ class Solution(ThermoPhase, Kinetics, Transport):
     def __init__(self, *args, **kwars):
         pass
 
+class Interface(InterfacePhase, Kinetics):
+    pass
diff --git a/interfaces/cython/cantera/thermo.pyx b/interfaces/cython/cantera/thermo.pyx
index d9f86e525..70e5b3828 100644
--- a/interfaces/cython/cantera/thermo.pyx
+++ b/interfaces/cython/cantera/thermo.pyx
@@ -22,3 +22,17 @@ cdef class ThermoPhase(_SolutionBase):
             cdef np.ndarray[np.double_t, ndim=1] X_c = np.empty(self.nSpecies)
             self.thermo.getMassFractions(&X_c[0])
             return X_c
+
+
+cdef class InterfacePhase(ThermoPhase):
+    cdef CxxSurfPhase* surf
+    def __cinit__(self, *args, **kwargs):
+        if self.thermo.eosType() not in (thermo_type_surf, thermo_type_edge):
+            raise TypeError('Underlying ThermoPhase object is of the wrong type.')
+        self.surf = <CxxSurfPhase*>(self.thermo)
+
+    property siteDensity:
+        def __get__(self):
+            return self.surf.siteDensity()
+        def __set__(self, double value):
+            self.surf.setSiteDensity(value)